Medical Student Research Fellowship for Summer 2005

Mentor: Stephen R Hammes
Department: Internal Medicine
Room number: Y9.310
Mail Code: 8857
Phone number: 214-648-3749
E-mail: stephen.hammes@utsouthwestern.edu
Project title: Steroid Signaling in the Ovary

Human subjects IRB approved project number (where applicable):

Animal subjects IRB approved project number (where applicable): 0867-01-01-1

Project Type (patient-based research, animal-based research, or basic research; this characterization is only to permit a general classification for grouping similar types of projects) Basic Research

Brief Description of Project:
Our lab studies how steroid hormones mediate transcription-independent, or nongenomic, effects. Examples of nongenomics steroid-triggered signals includes estrogen-mediated upregulation of nitric oxide synthase in endothelial cells, vitamin D-induced increases in intracellular calcium in osteosarcoma cells, and steroid-induced maturation of frog and fish oocytes. These signaling events may mediate important biological processes such as blood vessel relaxation, bone metabolism, and fertilization.
We use the phenomenon of androgen-induced maturation, or meiotic resumption, of frog and mouse oocytes to study nongenomic steroid signaling. Our interest in this system is three-fold: First, in contrast to the other processes described above, androgen-induced oocyte maturation is reproducible, biologically relevant, and easily measured. Second, oocytes can be manipulated in vitro to study androgen-mediated events. Finally, while physiologic levels of androgens appear to be important for normal oocyte development, supraphysiologic concentrations may be promoting ovarian pathology, as seen in polycystic ovarian disease (PCOS). We are interested in characterizing the role of classical steroid receptors and other signaling molecules in regulating the maturation response.
We hope that our studies will lead to a better understanding of how steroids can signal independent of transcription. Further, we hope that our work will further elucidate the critical role of androgens in ovarian development and pathology.

Previous Research Activities or Publications with Medical Students:

Bruce, Kristin and Hammes, S.R., Nongenomic Actions of Progesterone in Xenopus Oocytes, Poster presented at the 39th Medical Student Research Forum.
Stair, Matthew and Hammes, S.R., Differential Sensitivities of the Xenopus Androgen Receptor and the Human Androgen Receptor, Oral Presentation at the 40th Medical Student Research Forum.
Cowling, C.L., Gill, A., Lutz, L.B., Jahani, D., Rasar, M., and Hammes, S.R., The Role of the Androgen Receptor in Xenopus Laevis Oocyte Maturation, Poster presented at the 41st Medical Student Research Forum.

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